Pernasal composition and pernasal preparation containing the same

ABSTRACT

A pernasal composition containing a pharmacologically active substance, water and an alcohol, wherein the alcohol content is 10-70 vol. % of the whole composition. This composition is highly safe and permits rapid drug absorption and prolonged retention of blood drug level. Hence this composition and a pernasal preparation containing the same permit pernasal administration of drugs, which have been difficult to administer pernasally, and are expected to exhibit satisfactory drug efficacy.

TECHNICAL FIELD

This invention relates to a pernasal composition (pernasallyadministrable composition) and a pernasal preparation (pernasallyadministrable preparation) and more particularly to a novel compositionand a novel preparation which are very low in irritation to nasalmucosae and enable their pharmacologically active ingredients to behighly pernasally absorbed.

The pernasally administrable composition and preparation are hereinafterreferred to respectively as "pernasal composition" and "pernasalpreparation" for brevity.

BACKGROUND TECHNIQUES

It has heretofore been known that pharmaceutical compounds having highhydrophilicity and a low oil/water distribution ratio are not absorbablethrough digestive tracts or are extremely difficultly absorbabletherethrough. In general, a peptide or protein having a physiologicalactivity is extremely difficultly absorbable through the digestivetracts since it not only has high hydrophilicity and a low oil/waterdistribution ratio but also is subject to decomposition with enzymespresent in the digestive tracts or on the wall thereof.

Further, since many medicines absorbed through the digestive tracts aresubject to an initial passage effect in a liver, it has hitherto beennecessary to administer a medicine such as a peptide or protein having aphysiological activity by injection in order to expect full efficacyfrom the medicine so administered. However, since administration of sucha medicine by injection is not allowed to be executed by those otherthan specialists in the art and is also accompanied with pain given tothe administered, there is demanded a medicinal preparation which may beadministered in a more expedient and more feasible manner especially ina case where frequent administration of the preparation is required.

Pernasal administration of preparations adapted for pernasal absorptionhas recently been noted as a substitute for administration by injection.

Nasal mucosae have abundant capillary vessels and are satisfactory inabsorption of medicines therethrough as compared with vaginal mucosae,and, in addition, medicines absorbed directly into the capillary vesselsare advantageous in that, for example, they can avoid the initialpassage effect in a liver.

The medicines pernasally administered are not necessarily sufficient intheir biological availability and, therefore, the necessary dosage of apeptide or protein having a physiological activity must be large even ifpernasally administered as compared with that administered by injection.Further, the physiological variation (such as common cold and anallergy) of nasal mucosae will disadvantageously affect theabsorbability of medicines when administered.

Thus, fusigic acid derivatives, phospholipids, alkyl glucosides,saccharide fatty acid esters and surface-active agents proposedrespectively in Japanese Pat. Appln. Laid-Open Gazettes Nos. Sho61-33126 (or No. 33126/86), Hei 1-501550, Sho 63-243033, Sho 63-39882and Sho 52-25013, and the like have been used in attempts to enhance theabsorbability of pernasally administered medicines and reduce thedispersion of absorption thereof. These compositions and absorptionaccelerators so proposed in the above Japanese Gazettes have, inaddition to beneficial effects, a serious side-effect which isirritation to nasal mucosae, and, therefore, they are now still not putto practical use. Moreover, a part of antiseptics and preservativeswhich have been used in many conventional pernasally administrablepreparations have surface-activity and, therefore, a problem as to localirritation caused by said surface-activity begins to be raised (J.pharm. pharmacol, 1990, 42, 145-151).

Further, Japanese Patent Gazette No. Hei 3-38255 (No. 38255/91)describes that the use of hydroxypropylcellulose having a predeterminedviscosity will enhance the retentivity of a medicine at the nasalmucosae and increase the absorbability thereof, whereas it cannotnecessarily be said to be sufficiently effective.

It is thus eagerly sought to develop a pernasal composition and apernasal preparation each having lower irritation and each enabling itsactive ingredient to be highly absorbed.

Alcohols, on the other hand, have been used as a component for acomposition for pernasal use as described in Japanese Pat. Appln.Laid-Open Gazettes Nos. Sho 61-267528, Hei 1-160916, Sho 63-258821, andthe like; among others, propylene glycol, a low irritative, has beenused before as a base for an oral or injection preparation and has beenconfirmed to be safe, and, therefore, it has been used as an additive inmany cases.

However, according to descriptions made in the above Japanese Pat.Appln. Laid-Open Gazettes Nos. Sho. 1-267528, Hei 1-160316, Hei1-501708, Hei 1-501709 and the like, alcohols have been added topernasal preparations mainly as an antiseptic, osmotic pressureadjuster, solubilizer or moisture retainer in a concentration ofgenerally about 5% by weight.

Additionally, propylene glycol is added in an amount of about 10% as abase (Japanese Pat. Laid-Open Gazette No. Sho 62-283927) and in anamount of 20% as a solvent (Japanese Pat. Gazette No. Hei 4-38728). Themedicine to which propylene glycol is added in these cases is limited toa steroid, and the amounts of propylene glycol added are made to be aslarge as indicated above in view of the solubility of the principalingredient (which is the steroid in these cases).

Alcohols, however, are described in the above Gazettes as an ingredientfor use in medicinal preparations for local administration, and saidGazettes describe nothing about the change of absorbability of themedicine due to the addition of propylene glycol thereto. Thus, itcannot be anticipated from said Gazettes as mentioned later thatphysiologically active peptide, physiologically active protein and thelike will increase their absorbability through nasal mucosae due toactions such as inhibition, caused by propylene glycol, of the reactionof decomposition enzymes on the mucosae, and said Gazettes treat of orrefer to nothing about the primary irritation of propylene glycol to thenasal mucosae.

Only Japanese Pat. Appln. Laid-Open Gazette No. Hei 1-160916 illustratespropylene glycol as an absorption accelerator, but it does not clearlyindicate the amount of propylene glycol contained in a medicinalcomposition or preparation although it indicates the amount of propyleneglycol in terms of a ratio to dopamine which is a main pharmacologicallyactive substance, wherefrom it is impossible to easily infer the effectsof this invention on pharmacologically active substances.

Apart from the pernasal compositions, it has been appreciated thatpropylene glycol provides skin keratin with moisture retentivity andincreases a medicine in percutaneous absorption as described in, forexample, Japanese Pat. Appln. Laid-Open Gazettes Nos. Sho 62-51617 (orNo. 51617/87) and Sho 62-51619, but it is not easy to infer thatpropylene glycol is also effective for accelerating absorption of amedicine through the nasal mucosa having no keratin which is a barrierto absorption of a medicine and that propylene glycol will exhibit lowirritation when administered to the mucosa since, for example, it raisesa problem as to its primary irritation to skin when it is applied to theskin ("SKIN", vol. 26, 1119-1127, October 1984).

An alcohol other than propylene glycol, which is applicable to pernasalcompositions, is ethanol for illustration as described in Japanese Pat.Appln. Laid-Open Gazette No. Sho 63-13965, but a medicinal componentdiscussed in this Gazette is restricted to ergot alkaloid and furtherrestricted to a case where it is administered with use of a supersonicaerosol apparatus. The most preferable solvent used here is said to beone having an ethanol content of 10%, but this content of ethanol willleave a problem as to irritation to nasal mucosae unsolved.

Moreover, Japanese Pat. Appln. Laid-Open Gazette No. Sho 61-267528illustrates benzyl alcohol and ethanol as absorption accelerators. Themedicine used in this Gazette is limited to calcitonin and, further,ethanol is said to be used in a particularly preferable ratio of 1 to10% (w/v) between ethanol and a preparation containing the same.

This invention has been made in view of the facts and circumstances sofar mentioned, and an object thereof is to provide novel pernasalcompositions which eliminate the defects the conventional ones have had,have a specific formulation of a base thereof, exhibit low irritationand enable the active ingredient of the compositions to be pernasallyabsorbed at a high absorption rate and also to provide novelpreparations which contain the novel pernasal composition or to whichthe novel composition is applicable.

DISCLOSURE OF THE INVENTION

The present inventors made intensive studies of various compositions inattempts to overcome the foregoing problems or defects and, as a resultof their studies, they found that said defects can surprisingly beovercome by incorporating a pharmacologically active ingredient withwater and an alcohol in a specific ratio determined depending on theactive ingredient. This invention has thus been accomplished on thebasis of the above finding.

The object of this invention may be achieved by providing either apernasal composition which comprises a pharmacologically activeingredient, water and 10-70 vol. % of an alcohol based on the volume ofthe whole composition, or a pernasal preparation which contains saidcomposition or to which said composition is applicable.

The alcohols used in this invention may be any one, and it is preferablethat they be a lower alcohol having 1-4 carbon atoms, a lower alkanediolhaving 2-5 carbon atoms or a lower alkanetriol having 3-6 carbon atoms.

These preferable alcohols may include methanol, ethyl alcohol, n-propylalcohol, isopropyl alcohol, n-butyl alcohol, ethylene glycol(1,2-ethanediol), propylene glycol (1,2-propanediol), 1,3-propanediol,1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol,1,5-pentanediol and glycerine.

These alcohols may be used singly or jointly, and may be contained inthe medicinal composition in an amount by volume of 10-70%, preferably15-50% and more preferably 15-30% based on the whole composition (100vol. %). In general, the preferable alcohol content may suitably bedetermined within the above-mentioned range of alcohol contentsdepending on the kinds of alcohols used, combinations thereof and thelike.

Further, when at least two kinds of alcohols are required to be used inadmixture depending on the properties (such as solubility) of apharmacological active ingredient used in this invention, it isallowable as required to use, as a member of a mixture of alcohols, evenethyl alcohol or the like which will raise a problem as to irritation tomucosae and the like when used singly as previously mentioned.

The upper ratio in which alcohols are contained in a medicinalcomposition may suitably be determined depending on the kinds ofalcohols used, combinations of the alcohols, and the like, and, in thiscase, it is a matter of course that the effect or advantage, cost andside effect (particularly, irritation) to be derived from alcoholscontained be required to be taken into consideration for making suchdetermination as above.

Propylene glycol is particularly preferable among said alcohols in viewof, for example, the fact that it has somewhat been practically used asan additive to pharmaceuticals. The content of propylene glycol(1,2-propanediol) in a composition may preferably be 15-30% by volume ofthe whole composition.

Further, water used in this invention may be any one of purified water,a physiological saline solution, a buffer solution used for adjustmentof pH, and the like. The water or these solutions may be contained in anamount by volume of 1-90%, preferably 20-87% and more preferably 70-85%,based on the whole composition (100% by volume). The preferred contentof these aqueous liquids may suitably be determined within theabove-mentioned ranges depending on the kinds of the aforesaid alcoholsused, combinations thereof, and the like.

Still further, pharmacologically active substances used in thisinvention may be any such substance as far as it is absorbable through anasal mucosa, and such active substances usable particularly effectivelyin this invention are a medicine which is highly subject to an initialpassage effect in a liver, a medicine which is highly water-soluble andwill not sufficiently be absorbed when orally administered and amedicine which is remarkably decomposable in digestive tracts. Moreparticularly, such active substances include physiologically activepeptide, physiologically active protein, and possible salts andderivatives as well as isomers and optical isomers of the above peptideand protein. At least two of such active substances may also be used inadmixture.

The pharmacologically active substances used herein include insulin,calcitonin calcitonine gene related peptide, vasopressin, desmopressin,protirelin (TRH), adrenocorticotropic hormone (ACTH), luteinizinghormone-releasing factor (LH-RF), growth hormone-releasing hormone(GRH), nerve growth factor (NGF) and its releasing factor, angiotensin,parathyroid hormone (PTH), thyroid stimulating hormone (TSH,thyrotropin), follicle stimulating hormone (FSH), luteinizing hormone(LH), prolactin, serum gonadotropin, pituitary hormone (HCG), growthhormone, somatostatin, somatomedin, oxytocin, glucagon, gastrin,secretin, endorphin, enkephalin, endoserine, cholecystokinin,neurotensin, interferon, interleukin, transferrin, erythropoietin,superoxide dismutase (SOD), filgrastim (G-CSF), renin, vasoactiveintestinal polypeptide (VIP), muramyl dipeptide, corticotropin,urogastrone, atrial natriuretic polypeptide (h-ANP), estrogen,progesterone and adrenocorticosteroid hormone.

Among these pharmacologically active substances, it is preferable to usea relatively low-molecular weight peptide selected from amongcalcitonin, calcitonin gene related peptide (CGRP), vasopressin,desmopressin, protirelin (TRH), adrenocorticotropic hormone (ACTH),luteinizing hormone releasing factor (LH-RH), growth hormone-releasinghormone (GRH), growth hormone, oxytocin and muramyl dipeptide, andpossible salts, derivatives, isomers and optical isomers thereof, andmixtures of two or more of them.

Further, it is still preferable to use protirelin (TRH) which is aphysiologically active peptide having a lower molecular weight, andpossible salts, derivatives, isomers and optical isomers thereof, andmixtures of two or more of them.

The pernasal composition of this invention or the pernasal preparationwhich contains said composition or to which said composition isapplicable, together with or without a water-soluble or amphipathicpolymer added as a thickner or gelling agent for enhancing theretentivity of a medicine on the nasal mucosae, is filled in droppingbottles, sprayers, nasal aerosol applicators or the like in the form ofan aqueous solution thereof and then used for practical administration.

The thickners or gelling agents include known polymeric compounds suchas polysaccharide, gelatin, polyvinyl alcohol and derivatives thereof,carboxyvinyl polymer, polyethylene glycol, polyvinyl methyl ether-maleicanhydride copolymer and alkyl esters thereof, alcohol soluble nylon andpolyvinyl pyrrolidone-vinyl acetate copolymer; however, they may be anypolymeric compound as long as it is soluble in the above composition orpreparation of this invention.

Further, the pernasal composition of this invention may be used in theform of liposome, microsphere, microcapsule, nanoparticle or the likedepending upon the chemical properties of medicines in the compositionor the necessity occurring in manufacturing medicinal preparations. Thepernasal composition of this invention can be formulated intopreparations of these forms by mixing, dissolving, suspending,emulsifying or reacting necessary components in a suitable arbitraryorder by any conventional means.

If necessary, the pernasal preparation of this invention may furthercontain a predetermined amount of one or more members suitably selectedfrom among additives which are conventionally used for liquidpreparations for pernasal administration or external use and theadditives include microbicide, antiseptic, emulsifying agent,solubilizer, stabilizer, ultraviolet absorber and antioxidant.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a graph showing changes in plasma TRH-T concentration with thelapse of time, which changes were observed in tests using therein TRH-Tas a medicine and rats as test animals.

Fig. 2 is a graph showing changes in blood TRH-T concentration with thelapse of time, which changes were observed in tests using therein TRH-Tas a medicine and rats as test animals.

FIG. 3 is graph showing the results of evaluation tests on inhibition ofthe reactions of decomposition enzymes, the tests having been conductedby the use of an enzyme liquid obtained from rabbit nasal mucosae.

BEST MODE FOR CARRYING OUT THE INVENTION

This invention will now be explained in more detail by use of thefollowing Examples, though it is not limited thereto.

EXAMPLES 1 TO 9 AND COMPARATIVE EXAMPLES 1 TO 13

Several preparations containing protirelin tartrate (hereinafterabbreviated to "TRH-T") as a model medicine were evaluated forabsorption rate of the medicine, sustention of medicine release,irritation to nasal mucosae and inhibition of the reaction ofdecomposition enzymes by the use of rats and rabbits as test animals inthe following methods.

<<1. Evaluation tests on preparations for absorption rate of medicine>>

A predeterminded number of rats were narcotized with urethane, whilesample preparations of Examples 1 to 3 and Comparative Examples 1 to 5were formulated as will be described below. The sample preparations ofExamples 1 to 3 and Comparative Examples 1 to 3 were each pernasallyadministered to a part of the rats at their right nostril in an amountof 30 μl per rat. On the other hand, the sample preparation ofComparative Example 4 was intravenously administered to another part ofthe rats and that of Comparative Example 5 was intramuscularlyadministered to still another part of the rats, each in an amount of 150μl per rat. Thereafter, blood specimens were collected from the rats 5,10, 30 and 60 minutes after the administration and examined for plasmaTRH-T concentration by HPLC.

Ex. 1: 1 ml of a sample preparation was prepared by dissolving 50 mg ofTRH-T in a solution prepared by mixing water with propylene glycol at avolume ratio of 8.9:1.1.

Ex. 2: 1 ml of a sample preparation was prepared by dissolving 50 mg ofTRH-T in a solution prepared by mixing water with propylene glycol at avolume ratio of 8:2.

Ex. 3: 1 ml of a sample preparation was prepared by dissolving 50 mg ofTRH-T in a solution prepared by mixing water with propylene glycol at avolume ratio of 7:3.

Comp. Ex. 1: 1 ml of a sample preparation was prepared by dissolving 50mg of TRH-T in a solution prepared by mixing water with propylene glycolat a volume ratio of 9.5:0.5.

Comp. Ex. 2: 1 ml of a sample preparation was prepared by dissolving 50mg of TRH-T in a predetermined amount of a solution of 2 g ofhydroxypropylcellulose (viscosity: 1000 to 4000 cP as determined at 20°C. as 2% aqueous solution) in 100 ml of distilled water.

Comp. Ex. 3: 1 ml of a sample preparation was prepared by dissolving 50mg of TRH-T in a physiological saline solution.

Comp. Ex. 4: 1 ml of a sample preparation was prepared by dissolving 10mg of TRH-T in a physiological saline solution.

Comp. Ex. 5: 1 ml of a sample preparation was prepared by dissolving 10mg of TRH-T in a physiological saline solution.

<Result 1>

The results of the above evaluation tests are given in Table 1 andFIG. 1. In the Table and Figure, each plasma TRH-T concentration isgiven in μg/ml, while each AUC (biological availability) value is givenin μg min/ml. The sample preparations were administered respectively togroups each consisting of five rats (n=5) and the plasma TRH-Tconcentrations in Table 1 are expressed in terms of "average±standarderror". The plasma TRH-T concentration 0 minute after the intravenousadministration was expressed in terms of an average of concentrationvalues obtained with each of the rats at that time by extrapolation.Further, each AUC value was calculated from the average plasma TRH-Tconcentrations at respective measuring times according to thetrapezoidal rule.

As apparent from the results given in Table 1 and FIG. 1, the plasmaTRH-T concentration attained in Example 1 is apparently higher than thatattained in Comparative Example 3 of a simple composition using aphysiological saline solution. Further, the sample preparations ofExamples 2 and 3 exhibit that the absorption rate of the medicine ishigher, that is, the absorption of TRH-T is accelerated to give a highplasma TRH-T concentration at an earlier stage than those of all of theComparative Examples except Comparative Example 4 (intravenousadministration). Further, it is apparent from the results that theabsorbability of a medicine through nasal mucosae is enhanced by addingan alcohol to the water of the sample preparation and the accelerationof absorption varies depending upon the amount of the alcohol added.

By virtue of the acceleration of absorption of the medicine due to theaddition of the alcohol, Example 1 (wherein 11% by volume of propyleneglycol was contained) gives a biological, availability (AUC) nearlyequivalent to that of Comparative Example 5 (intramuscularadministration); Example 2 (wherein 20% by volume of propylene glycolwas contained) exhibits nearly maximum acceleration of absorption; andsuch high biological availability is maintained also in Example 3(wherein 30% by volume of propylene glycol was contained). Further, thebiological availabilities attained in Examples 2 and 3 reach about 50%of that attained in Comparative Example 4 (intravenous administration),which reveals that full efficacy of the medicine can be realizedaccording to this invention.

In a case where a combination of TRH-T with propylene glycol is used,the addition of the alcohol in an amount of 20% by volume or above doesnot give any additional acceleration, from which it may be presumed thatthere is a minimum amount of an alcohol necessitated for attaining themaximum acceleration of absorption of a medicine, though the minimumamount varies depending upon the kinds of the medicine and alcohol to becombined.

Although there are observed in Comparative Example 2 the effect ofsustaining the release of the medicine due to enhanced retention of themedicine on nasal mucosae and an increase in the AUC value, such speedyabsorption of the medicine as attained in Example 2 or 3 according tothis invention is not observed in Comparative Example 2 and it isdifficult to say that the biological availability attained inComparative Example 2 is sufficiently high.

                  TABLE 1                                                         ______________________________________                                        0 min.     5 min.  10 min.  30 min.                                                                             60 min.                                     after      after   after    after after AUC                                   ______________________________________                                        Ex. 1  0.00 ±                                                                             0.93 ±                                                                             2.06 ±                                                                            2.44 ±                                                                           0.98 ±                                                                           106.10                                     0.00    0.57    0.23   0.93  0.21                                      Ex. 2  0.00 ±                                                                             6.45 ±                                                                             7.00 ±                                                                            1.30 ±                                                                           0.33 ±                                                                           157.20                                     0.00    1.03    1.21   0.36  0.12                                      Ex. 3  0.00 ±                                                                             6.65 ±                                                                             7.10 ±                                                                            1.25 ±                                                                           0.34 ±                                                                           158.35                                     0.00    1.11    1.28   0.33  0.13                                      Comp.  0.00 ±                                                                             0.73 ±                                                                             1.10 ±                                                                            1.52 ±                                                                           0.40 ±                                                                            61.40                              Ex. 1  0.00    0.41    0.15   0.56  0.11                                      Comp.  0.00 ±                                                                             1.72 ±                                                                             1.81 ±                                                                            1.71 ±                                                                           1.45 ±                                                                            95.73                              Ex. 2  0.00    0.41    0.57   0.65  0.46                                      Comp.  0.00 ±                                                                             0.53 ±                                                                             1.02 ±                                                                            1.53 ±                                                                           0.30 ±                                                                            58.15                              Ex. 3  0.00    0.21    0.33   0.42  0.14                                      Comp.  39.25 ±                                                                            16.76 ±                                                                            7.48 ±                                                                            0.81 ±                                                                           0.57 ±                                                                           304.23                              Ex. 4  3.04    1.11    0.61   0.35  0.28                                      Comp.  0.00 ±                                                                             1.01 ±                                                                             2.04 ±                                                                            2.57 ±                                                                           0.83 ±                                                                           107.25                              Ex. 5  0.00    0.42    0.24   0.31  0.36                                      ______________________________________                                    

<<2. Evaluation tests on preparations for release-sustaining effect onmedicine>>

A predetermined number of rats were narcotized with urethane, whilesample preparations of Example 4 and Comparative Examples 6 and 7 wereprepared as will be described below. The sample preparation of Example 4was pernasally administered to a part of the rats at their right nostrilin an amount of 20 μl per rat. On the other hand, the sample preparationof Comparative Example 6 was intravenously administered to another partof the rats, while that of Comparative Example 7 was subcutaneouslyadministered to still another part of the rats, each in an amount of 100μl per rat. Thereafter, blood specimens were collected from the rats 3,5, 10, 15, 20, 30, 45, 60, 90, 120 and 180 minutes after theadministration and examined for blood TRH-T concentration byradioimmunoassay (RIA).

Ex. 4: 1 ml of a sample preparation was prepared by dissolving 100 mg ofTRH-T in a solution prepared by mixing water with propylene glycol at avolume ratio of 8:2.

Comp. Ex. 6: 1 ml of a sample preparation was prepared by dissolving 20mg of TRH-T in a physiological saline solution.

Comp. Ex. 7: 1 ml of a sample preparation was prepared by disolving 20mg of TRH-T in a physiological saline solution.

<Result 2 >

The results of the above evaluation tests are given in FIG. 2. In FIG.2, each blood TRH-T concentration is given in ng/ml. The samplepreparations were administered respectively to groups each consisting offive rats (n=5) and each blood TRH-T concentration is expressed in termsof "average±standard error".

As apparent from the results given in FIG. 2, the blood TRH-Tconcentration in Example 4 is kept at a higher level than those inComparative Examples 6 and 7 after the lapse of 60 minutes or more sincethe administration. From these results, it is apparent that by making amedicine absorbed through nasal mucosae by the use of the composition ofthis invention comprising the medicine, water and further an alcoholadded to the water, not only the temporary absorption of the medicine isaccelerated like in Result 1, but also the effect of sustained releaseof the medicine is attained. In Example 4, further, the blood TRH-Tconcentration is kept at a high level over a long period of time ascompared with the case of subcutaneous administration (ComparativeExample 7) known as being effective for sustained release of medicine,and additionally, the absorption rate of Example 4 is not far differentfrom that of Comparative Example 7. Accordingly, the release-sustainingeffect according to this invention is very excellent.

<<3. Evaluation tests on preparations for irritation to nasal mucosae>>

Preparations of Examples 5 and 6 and Comparative Examples 8 to 11prepared as will be described below were each pernasally administered tourethane-narcotized rats in an amount of 30 μl per rat. Two hours afterthe administration, a nasal septum was extirpated from each of the ratsaccording to the conventional method for preparing a sample for scanningelectron microscopy (SEM).

The nasal septa thus extirpated were subjected to tissue fixation,critical point drying and gold vapor deposition, and thereafter thesurfaces of the resulting nasal septa were observed under a scanningelectron microscope (SEM).

The extent of the damage to each mucosa surface was judged according tothe criteria specified in Table 2 and an average of the extents thusjudged is regarded as an irritation index of a particular samplepreparation to nasal mucosae.

                  TABLE 2                                                         ______________________________________                                        Judgement     State of the nasal mucosa                                       ______________________________________                                        0             normal                                                          1             abnormality is observed on the villi                            2             enlarged intercellular spacing of the                                         nasal mucosa                                                    3             cell liberation of the nasal mucosa                             4             cell aggregation of the nasal mucosa                            5             exfoliation and escape of cells of the                                        nasal mucosa with exposed basement                                            membrane                                                        ______________________________________                                    

Ex. 5: A solution prepared by mixing water with propylene glycol at avolume ratio of 8.9:1.1.

Ex. 6: A solution prepared by mixing water with propylene glycol at avolume ratio of 8:2.

Comp. Ex. 8: A physiological saline solution.

Comp. Ex. 9: 1 ml of a sample preparation is prepared by dissolving 0.5%(w/v) of polyoxyethylene lauryl ether (oxyethylene: ca. 9 units,hereinafter abbreviated to "BL-9") in a physiological saline solution.

Comp. Ex. 10: A commercially available pernasally administrable drug A(systemic) "SUPRECUR" (buserelin acetate) (registered trademark), aproduct of Hoechst, systemic-action preparation.

Comp. Ex. 11: A commercially available pernasally administrable drug B(local), "PRIVINA" (naphazoline nitrate) (registered trademark), aproduct of Ciba Geigy, local-action preparation.

<Result 3>

The results of the above evaluation tests are given in Table 3. Asapparent from Table 3, the sample peparations of Examples 5 and 6 hadirritation equivalent to or lower than those of the commerciallyavailable nasal drops of Comparative Examples 10 and 11. Accordingly, itcan be understood that the pernasal composition of this invention is alow irritant to nasal mucosae:

                  TABLE 3                                                         ______________________________________                                                              Irritation Index to                                     Test sample     n     Nasal Mucosae                                           ______________________________________                                        Ex. 5           10    0.6                                                     Ex. 6           10    0.8                                                     Comp.           10    0.05                                                    Ex. 8                                                                         Comp.           10    3.2                                                     Ex. 9                                                                         Comp.           10    1.2                                                     Ex. 10                                                                        Comp.           10    2.1                                                     Ex. 11                                                                        ______________________________________                                    

<<4. Evaluation tests on preparations for inhibitive action ondecomposition enzymes>>

Rabbit nasal mucosas were homogenized in a physiological saline solutionand the thus obtained homogenate was centrifuged. The supernatant thusobtained was used as an enzyme liquid. Sample preparations of Examples 7to 9 and Comparative Examples 12 and 13 were each prepared by the use ofthis enzyme liquid as will be described below and incubated in a warmwater bath at 37° C. to determine changes of the amount of the medicineremaining in the preparation with the lapse of time by HPLC.

Ex. 7: 20 μg of TRH-T were dissolved in a solution prepared by mixing1.30 ml of the enzyme liquid with 0.21 ml of propylene glycol and 0.49ml of a physiological saline solution (the sample preparation having apropylene glycol content of 10 vol %).

Ex. 8: 20 μg of TRH-T were dissolved in a solution prepared by mixing1.30 ml of the enzyme liquid with 0.40 ml of propylene glycol and 0.30ml of a physiological saline solution (the sample preparation having apropylene glycol content of 20 vol %).

Ex. 9: 20 μg of TRH-T were dissolved in a solution prepared by mixing1.30 ml of the enzyme liquid with 0.60 ml of propylene glycol and 0.10ml of a physiological saline solution (the sample preparation having apropylene glycol content of 30 vol %).

Comp. Ex. 12: 20 μg of TRH-T were dissolved in a solution prepared bymixing 1.30 ml of the enzyme liquid with 0.10 ml of propylene glycol and0.60 ml of a physiological saline solution (the sample preparationhaving a propylene glycol content of 5 vol %).

Comp. Ex. 13: 20 μg of TRH-T were dissolved in a solution prepared bymixing 1.30 ml of the enzyme liquid with 0.70 ml of a physiologicalsaline solution.

<Result 4>

The results of the above evaluation tests are given in FIG. 3. As shownin FIG. 3, the sample preparations containing propylene glycol in anamount of 10 vol % or above exhibited an enzyme-inhibiting effect, andin particular, the sample preparations containing the same in an amountof 20 vol % or above inhibited the action of the enzymes nearlycompletely.

As described above, it is apparent that the pernasal composition of thisinvention has an inhibition effect against peptidases on nasal mucosae,which means that one of the mechanisms for the absorption acceleratingeffect of this invention is inhibition of a reaction of decompositionenzymes and that the composition of this invention is particularlysuitable for the administration of a peptide.

In a case where a combination of TRH-T with propylene glycol is used,the inhibition effect against decomposition enzymes will be maximizedwhen a propylene glycol content of 20 vol % is reached like in Result 1.This indicates that there is a minimum alcohol content necessitated forattaining the maximum inhibition effect against the action ofdecomposition enzymes, though the minimum one varies depending upon thekinds of the medicine and alcohol to be combined.

Industrial Applicability

As described above, it is apparent that excellent absorption of amedicine can be attained by using the pernasal composition of thisinvention prepared by incorporating a pharmacologically active substancewith water and an alcohol in a specific ratio or using the pernasalpreparation of this invention containing said composition.

The mechanism of action contributing to the absorption-acceleratingeffect according to this invention is an inhibitive action on enzymeswhich decompose peptide. In this respect, the pernasal composition ofthis invention is different from that of the conventional acceleratedabsorption type (particularly, a conventional one exhibiting surfaceactivity, e.g., the sample preparation of Comparative Example 9) whichpartially changes or destroys the structure of the mucosal epithelium toattain accelerated permeation of a medicine. Therefore, it is apparentthat the pernasal composition of this invention is a remarkably lowirritant and is not noxious to the tissue.

As described above, the pernasal composition of this invention is highlysafe and enables not only speedy absorption of a medicine but alsomaintenance of blood medicine concentration at a high level for a longtime, thus permitting the provision of a pernasal preparation which canbe expected to attain high efficacy. Further, since a pernasalpreparation can be generally easily administered to patients even bythemselves or helpers without relying upon doctors, the use of thepernasal preparation of this invention makes it possible to administer amedicine, which has conventionally been difficultly capable of pernasaladministration, not only singly but also frequently with remarkablereduction in the pains of patients and the labor of doctors. Thus, thisinvention is particularly useful for the pharmaceutical industry.

Additionally, water and alcohols, which are used in this invention asthe raw materials, are extremely easily mixable and are excellent instability. Therefore, this invention can dispense with the addition of asolubilizer and emulsification which have been necessitated in preparinga conventional accelerated absorption type pernasally administrablecomposition containing an absorption accelerator, this indicating thatthe pernasal composition of this invention is so excellent also inproducibility and manageability as to be industrially useful in theserespects.

What is claimed is:
 1. A pernasal composition consisting of:1) apharmacologically active substance selected from the group consisting ofa physiologically active peptide, a physiologically active protein, asalt, isomer or optical isomer of said peptide or protein, and mixturesthereof, 2) a member selected from the group consisting of purifiedwater, a physiological saline solution and a buffer solution; and 3)10-70% by volume of propylene glycol based on the whole composition; andoptionally 4) at least one additive selected from the group consistingof a water-soluble polymeric thickener and a water-soluble polymericgelling agent.
 2. A pernasal composition according to claim 1, whereinsaid propylene glycol is contained in an amount of 15-30% by volume ofthe whole composition.
 3. A pernasal composition according to claim 1,wherein said pharmacologically active substance is a member selectedfrom the group consisting of protirelin (TRH), a salt, isomer or opticalisomer of TRH, and mixtures thereof.
 4. A pernasal preparationcomprising a composition as claimed in claim 1 and at least one additiveselected from the group consisting of a microbicide, antiseptic,emulsifying agent, solubilizer, stabilizer, ultraviolet absorber andantioxidant.
 5. A pernasal preparation comprising a composition asclaimed in claim 2 and at least one additive selected from the groupconsisting of a microbicide, antiseptic, emulsifying agent, solubilizer,stabilizer, ultraviolet absorber and antioxidant.
 6. A pernasalpreparation comprising a composition as claimed in claim 3 and at leastone additive selected from the group consisting of a microbicide,antiseptic, emulsifying agent, solubilizer, stabilizer, ultravioletabsorber and antioxidant.
 7. A pernasal composition according to claim2, wherein said propylene glycol is contained in an amount of 20-30% byvolume of the whole composition.
 8. A pernasal composition according toclaim 1, wherein said pharmacologically active substance is aphysiologically active peptide selected from the group consisting ofcalcitonin, calcitonin gene related peptide (CGRP), vasopressin,desmopressin, thyrotrophin releasing hormone (TRH), adrenocorticotropichormone (ACTH), luteinizing hormone-releasing factor (LH-RH), growthhormone-releasing hormone (GRH), growth hormone, oxytocin and muramyldipeptide, and a salt, isomer or optical isomer of said peptide, andmixtures thereof.
 9. A pernasal composition according to claim 1, whichfurther comprises at least one thickener or gelling agent selected fromthe group consisting of polysaccharide, gelatin, polyvinyl alcohol,carboxyvinyl polymer, polyethylene glycol, polyvinyl methyl ether-maleicanhydride copolymer and an alkyl ester thereof, alcohol-soluble nylonand polyvinyl pyrrolidone-vinyl acetate copolymer.
 10. A method forpreparing a pernasal preparation, consisting of the step of dissolving aphysiologically active peptide or salt, isomer or optical isomer of saidpeptide, or a mixture thereof in an amount of 50-100 mg per milliliterof the whole preparation to be prepared, in a mixing solution of 70-89%by volume of purified water, a physiological saline solution or a buffersolution with 11-30% by volume of propylene glycol, each based on thevolume of the whole preparation to be prepared.
 11. A method accordingto claim 10, wherein the physiologically active peptide is athyrotrophin releasing hormone (TRH).
 12. A method according to claim11, wherein the thyrotrophin releasing hormone (TRH) is protirelin.